1. Field of the Invention
The present invention relates generally to a gas turbine combustor apparatus comprising a plurality of combustors and more particularly to a gas turbine combustor apparatus by which a combustion of a lean and uniform pre-mixture is realized in each of the plurality of combustors.
2. Description of the Prior Art
The gas turbine combustor apparatus comprises therein a plurality of combustors that are arranged along a circumferential direction around a gas turbine rotor. As shown in FIG. 2, each of the combustors 1 is constructed such that a pilot nozzle 8 is centrally arranged and a plurality of pre-mixing nozzle 8 are arranged around the pilot nozzle 8. Numeral 11 designates a swirling vane. While fuel is injected from a dual fuel nozzle 2 provided in the pre-mixing nozzle device 10 and is mixed with air to form a pre-mixture, such air is subjected to a swirling force by the swirling vane before it is mixed with the fuel.
While the dual fuel nozzle 2 is shown as comprising a plurality of pieces in the pre-mixing nozzle device 10, one example of the dual fuel nozzle 2 is shown in FIG. 3. This dual fuel nozzle 2 is constructed such that gas fuel led through a gas fuel flow passage 5 is injected from a gas fuel injection port 7 immediately downstream of the swirling vane 11 and liquid fuel led through a liquid fuel flow passage 4 is injected from a liquid fuel injection port 6 downstream of the gas fuel injection port 7. Incidentally, in FIG. 3, numeral 3 designates a rod member, which constitutes a fuel supply pipe, and numeral 9 designates a cylindrical pre-mixing nozzle member.
In the gas turbine combustor apparatus constructed by comprising such a multiplicity of combustors 1, in order to reduce NOx (nitrogen oxides) generated by combustion, it is necessary to realize a combustion of a lean and uniform pre-mixture in each of the combustors. For this purpose, in manufacturing the combustors, it is necessary to work each of the fuel nozzles of the combustors with a high degree of accuracy so that each of the nozzles may be made in the same dimensions and shapes. However, according to the accuracy of the currently available working technology, it is not always easy, but instead difficult, to obtain a desired uniformity of the accuracy for each of the nozzles and this presently there is accordingly a limitation in the NOx reduction also.